Casting polyurethane Elastomers can be many things. They can be strong, stiff, flexible, tough, resilient, durable, long-lasting…and they can also be both viscous and elastic. Polyurethane Elastomers are known for their extreme resilience and have therefore begun to see use in the manufacture of a number of vehicle and machinery parts. In particular, polyurethane elastomers are often used to produce fenders, fascia, trims, interior and exterior vertical panels, doors, chassis fairings, and window surrounds. They are also frequently seen as a component material in tires and wheels.
Advantages of Casting Polyurethane Elastomer
Friction Coefficients
Urethane can be formulated to offer various coefficients of friction that will remain permanently in your compound. This is usually not possible with other elastomers which may continue to cure, harden, or soften over their usual life, with resultant changes in the coefficient of friction.
Impact Resistance
With even the hardest urethanes, you can achieve significantly better impact resistance than plastics and composites. While conventional plastic materials can become brittle as they become harder, urethane retains elasticity and strength over the complete range of hardness.
Hardness
Urethane prepolymers can be formulated to cover a wide range of hardness, from 20 Shore A durometer (the hardness of a rubber band) to 75 Shore D durometer (the hardness of bone).
Hydrolytic Stability
Polyether based urethane prepolymer formulations have superior hydrolytic stability. They absorb practically no water (barely 0.3% to 1% by weight) and are suitable for applications requiring immersion.
-
![Three Componment MDI System Casting Polyurethane]()
Three Componment MDI System Casting Polyurethane
Add to Inquiry -
![Polyester Type MDI System Polyurethane Elastomer]()
Polyester Type MDI System Polyurethane Elastomer
Add to Inquiry -
![PTMEG Type MDI System Polyurethane Elastomer]()
PTMEG Type MDI System Polyurethane Elastomer
Add to Inquiry
Why Choose Us
Our Factory
Zibo Hengjiu PU Technology Co., Ltd. is a professional manufacturer which engaged in the R & D, production and sales of polyurethane prepolymer, polyester polyol and polyurethane elastomer finished products.
Advanced Equipment
The company has the most advanced production and testing equipment in China, has an annual production capacity of 30000 tons of various casting polyurethane prepolymers, polyester polyol and polyurethane elastomer finished products realizes the chain production from upstream raw materials to downstream products.
Production Market
The company's products not only spread all over the national market, but also exported to Canada, Australia, India, Turkey, Russia, Indonesia, South Korea, Malaysia and other international markets.
One-stop Solution
The company has a group of high-quality technical talents, which can provide customers with comprehensive services such as pre-sales, in-sales, after-sales and technical guidance.
Sporting Equipment, such as skateboard wheels, have been made with polyurethanes . Today, MDI ether-based polyurethanes are, however, producing wheels with greater resilience, good rebound and excellent abrasion resistance. As a result, skate boarders realize improved speed performance with a smoother ride. The variety of hardness ranges available with high performance polyurethanes is an added advantage. For example, small wheels with a durometer hardness of around Shore 75A are preferred for street skating while ramp skaters require larger, harder wheels that perform at high speeds without sliding.
Automotive components such as fender flairs and bumper covers must be durable and tough enough to withstand vibration and shock from traveling on roads and rough terrains. The parts must also endure weather and temperature extremes without cracking. A new TPO-like polyurethane based on advanced crosslinked technologies gives vehicle manufacturers the reliable performance they need. The same material is also easy to process, even on large vehicle parts.
Oilfield pigs and components are easier to mold and longer lasting with new MDI ester-based polyurethanes. The next-generation polyurethanes have a low viscosity that accommodates hand-batch or meter mixing and can be molded in low-cost epoxy tooling built to the broad variety of sizes and shapes required for the oil field application. (Aluminum molds machined to the numerous sizes needed would be prohibitively expensive and require long lead times that would not allow pig manufacturers to respond to customer needs in a timely manner.) The new polyurethanes cure at 150℉ (66℃) which is considerably lower than the temperatures required by “hot pour” TDI prepolymers, producing energy savings. Once cured, MDI ester-based polyurethanes exhibit good dimensional stability, ultra-high abrasion resistance, and excellent oil and chemical resistance.
Mining equipment coated with or cast using high-performance MDI and TDI ether-based polyurethanes requires less maintenance and replacement to substantially reduce operating costs. These polyurethanes are available in a range of durometers, from Shore A to Shore D hardnesses, making them suitable for use in nearly all mining environments. Other important properties for long-term durability include resistance to sliding and impact abrasion as well as cut and tear resistance. Typical applications include steel and wire-mesh screens coated with polyurethane, metal pump, chute and valve bodies lined with polyurethane, and cast polyurethane impellers.
Agricultural, manufacturing and other industrial parts represent an ever- growing market for high-performance polyurethanes. The most abrasive and harsh environments, including grain handling and textile manufacturing, benefit from MDI polyester polyol-based polyurethane-lined equipment for extended service life. In addition, for parts that come in contact with oats, wheat and cereals, some MDI ester-based polyurethanes are FDA-approved for dry food contact. TDI polyester-based, Shore A hardness polyurethanes exhibit high solvent resistance and mechanical properties for use in printing rollers.
MDI ether-based prepolymers mixed with diol curatives offer excellent hydrolysis resistance for casting agitators and other components produced for laundry equipment. TDI ether-based prepolymers combine hydrolysis resistance with hardness and dynamic stability even when exposed to changing operating temperatures. As a result, the materials handle use in components such as paper processing rollers. TDI ether amine-based polyurethanes exhibit outstanding abrasion resistance and high load bearing capacity for power transmission guide rollers.
With the many casting polyurethanes available on the market today, you can be certain that whatever hardness, elongation and flexural characteristics may be required for an application can be readily found among the various prepolymer/curative combinations.
Key benefits of many of the new high-performance polyurethanes are property combinations that were previously not available including: high heat, high impact, high modulus products as well as systems that can withstand exposure to gouging, cutting, chemicals, oils and solvents. Some high-performance products are also flame retardant.
Abrasion resistance is, in next-generation polyurethanes, a quantifiable property according to industry-standard Taber abrasion testing. While polyurethanes have long been recognized for their ability to resist wear in challenging applications, advanced polyurethanes exhibit wear loss in the 5 to 20 mg range.
Tear strength of new polyurethanes is also excellent compared with conventional hand-casting systems. Super-tough, new polyurethanes and polyurea hybrids offer tear strengths from 225 up to nearly 650 pli. Similarly, notched Izod impact strengths of next-generation polyurethanes is as high as 6.5 ft-lb/in. compared with < 1.0 ft-lb/in. for traditional products. Heat deflection temperatures are now in the 248℉ (120℃) to 346℉ (174℃) range.
The Casting Polyurethane Elastomer Molding Process
Like other thermoset polymers, elastomeric polyurethane is molded into parts via the reaction injection molding (RIM) process. Two liquid components, isocyanate and polyol, are stored in large tanks and transported via high-pressure pumps. The components are mixed inside an impinging mixer, where the chemical reaction of the two, within a mold, cross-link to form an elastomeric solid material.
As with all of our reaction injection molding parts, elastomeric parts utilize lightweight closed molds, usually constructed from aluminum. Heat and low pressure are applied during a short curing process of mere minutes. The elastomeric part emerges from the mold in a fully cured solid and ready for use. Also offers the unique opportunity of in-mold painting (IMP), in which the paint is applied directly to the mold surface, then it chemically bonds and transfers to the part within the molding cycle, eliminating the need for difficult and time-consuming post-mold painting.
Elastomeric polyurethane is also an excellent candidate for reinforced reaction injection molding (RRIM), in which glass, mineral, or carbon fibers are added to the liquid polymer to reinforce the completed parts. RRIM parts are stronger and tougher without needing to sacrifice the resilient elastic qualities for which elastomers are famed.
Choose the right material
Polyurethane casting involves mixing two or more components to create a chemical reaction that results in a solid, plastic-like material. It is important to choose the right materials for the job based on factors such as the desired properties of the final product, the complexity of the mold, and the intended application of the part.
Prepare the mold
The mold is a critical component of the casting process, and it must be carefully prepared to ensure that the polyurethane fills all of the cavities and spaces of the mold. The mold should be cleaned and lubricated before casting, and any necessary coatings or releases should be applied to prevent sticking.
Mix the polyurethane
The two or more components of the polyurethane should be measured and mixed according to the manufacturer's instructions. It is important to mix thoroughly to ensure a homogenous mixture, but not too vigorously, as this can introduce air bubbles into the mix.
Pour the polyurethane
Once the polyurethane is mixed, it should be poured slowly and steadily into the mold. Care should be taken to avoid introducing any air bubbles or gaps into the mold, as these can weaken the final product.
Allow to cure
Polyurethane usually takes several hours to cure, depending on the specific formulation and environmental conditions. The mold should be kept in a controlled environment during this time to ensure proper curing.
Demold the part
Once cured, the polyurethane part can be removed from the mold. Depending on the complexity of the mold and the nature of the part, this may require some care and precision to avoid damaging the part.
Casting Polyurethane Elastomer Compared to Structural Foams
Despite having many similarities, elastomeric RIM polyurethanes and structural polyurethane foams display different properties. For starters, structural foams are formed through a unique foaming process in which creates a dual-layer composition. This structure, similar to a hardboiled egg features a foamed inner core surrounded by a solid outer shell or “skin”. For this reason, structural foams are typically known for being extremely lightweight when compared to elastomeric polyurethanes. While both materials exhibit superior properties over injection-molded plastics, such as ABS or polyethylene, elastomeric polyurethanes can exhibit far greater tensile strength in high-stress environments. The primary use for structural foams is housings or cabinetries for high-end electronics or medical device equipment.
The Difference In Hardness Of Casting Polyurethane Elastomer
Firstly, polyurethane prepolymers with higher hardness provide better mechanical properties, such as impact resistance, abrasion resistance, and stiffness. This makes them ideal for applications requiring high durability, such as automotive parts, sports equipment, and industrial machinery. On the other hand, polyurethane prepolymers with lower hardness offer better flexibility and elasticity, making them suitable for applications requiring good adhesion, such as coatings, adhesives, and sealants.
Secondly, the NCO content of polyurethane prepolymers can vary depending on the hardness. NCO refers to the isocyanate groups present in the material, which are responsible for the reaction with polyols to form the final polyurethane product. Generally, higher hardness polyurethane prepolymers have higher NCO content, which results in faster curing and higher crosslink density. This makes them suitable for applications requiring quick and efficient processing, such as spray foam insulation and casting of complex shapes. In contrast, lower hardness polyurethane prepolymers have lower NCO content, which results in slower curing and lower crosslink density. This makes them suitable for applications requiring longer working times and better flowability, such as potting and encapsulation.
Thirdly, the catalyst type used in polyurethane prepolymers can also vary depending on the hardness. Catalysts are used to activate the isocyanate-polyol reaction and accelerate the curing process. Generally, higher hardness polyurethane prepolymers require stronger catalysts, such as tin-based catalysts, to achieve optimal curing performance. This is because the higher crosslink density makes it more difficult for the reaction to occur naturally. On the other hand, lower hardness polyurethane prepolymers require milder catalysts, such as amine-based catalysts, to prevent premature gelation and achieve better flowability.
Finally, the applicable scope of polyurethane prepolymers with different hardness varies depending on the specific application requirements. Generally, higher hardness polyurethane prepolymers are suitable for applications requiring high mechanical strength and durability, such as structural foam, elastomers, and rigid insulation. On the other hand, lower hardness polyurethane prepolymers are suitable for applications requiring flexibility and adhesion, such as coatings, adhesives, and sealants.
Polyurethane prepolymers with different hardness provide unique advantages in terms of performance, NCO content, catalyst types, and applicable scope. By understanding these characteristics, users can select the most suitable polyurethane prepolymer for their specific application needs.
Polyurethane elastomers have many excellent physical and mechanical properties, such as high elasticity, tear resistance, aging resistance, and wear resistance. These properties make them ideal materials for producing concrete pistons.
Different types of polyurethane elastomers can be used to match different types of performance concrete pistons. For example, a high-elasticity polyurethane elastomer is suitable for manufacturing pistons that require a larger deformation, while a wear-resistant polyurethane elastomer is suitable for pistons that need a longer service life.
Polyurethane elastomers have very important parameter indicators that determine their performance in concrete piston production. The hardness, tensile strength, elongation at break, tear strength, compression set, and fatigue properties are all important factors that determine the quality of the finished product.
The benefits of using polyurethane elastomers to produce concrete pistons are many. Firstly, they have a higher compression resistance than natural rubber, meaning they can create higher pressure.
Additionally, the properties of polyurethane elastomers can be customized to match the specific requirements of a given application. Finally, they provide a significant reduction in noise during use, which is important for reducing noise pollution in construction sites.
Polyurethane elastomers are a reliable and effective material for producing concrete pistons. With their numerous advantages and ability to match specific performance requirements, they offer a superior solution to natural rubber and other materials. By ensuring that the correct polyurethane elastomer type and parameters are used in piston production, builders and contractors can achieve the performance standards they require while also minimizing noise pollution.
FAQ
As one of the leading casting polyurethane elastomer manufacturers in China, we warmly welcome you to buy high-grade casting polyurethane elastomer made in China here from our factory. All our products are with high quality and competitive price. For more information, contact us now.
Polyether Based Casting Polyurethane Prepolymer, Cold Casting Polyurethane Prepolyer, PTMEG Type MDI System Polyurethane Elastomer